Are India’s latest COVID-19 vaccines more effective?

Both are based on second generation platforms known as protein vaccines which are safer than conventional platforms such as inactivated whole cell ones. Protein-based vaccines are made using specific particles of a virus that have the ability to generate an immune response, known as an anti-gen. The antigen is combined with an ‘adjuvant’ to trigger an immune response. In Covovax, a plant-based adjuvant known as saponin is combined with a protein of the first strain of SARS-CoV-2. Corbevax uses particles from the receptor-binding domain of the virus’s spike protein to trigger an immune response.

What is the recommended dosage?

Both are approved as two-dose vaccines within a one-month period. These vaccines are not yet recommended for children. The World Health Organization (WHO) has recommended a third dose of Kovavax for people with weakened immunity and also recommended its use in pregnant women. The WHO’s Scientific Advisory Group for Vaccine Effectiveness notes that although there are no data for Kovavax on pregnant women, previous experience using protein-based vaccines has been safe. The data for Corbevax is currently only available for adults. Detailed guidelines are awaited. However, the firm has started booster trials in India.

What are the benefits of protein based jabs?

They are safer because they do not use live or weakened virus particles that can cause vaccine-induced infections. This platform is dominated by several new generation vaccines such as Hepatitis B and HPV vaccines. The high safety profile makes them suitable for immunocompromised people. But they may not trigger a permanent immune response. That’s why a booster is needed.

Do these vaccines work against the variant?

Novavax (one of the firms behind Kovavax) said the third dose of the vaccine produced an enhanced immune response against Omicron and also provided a cross reactive immune response against delta-like variants. It is now developing an Omicron-specific jab, which is expected to go into production by January 2022. Corbevax does not yet have data on Omicron effectiveness, but it seems to trigger a better immune response against Delta than Covishield, which has more than 80% efficacy against it. Symptomatic infection.

When will they be available to the public?

Although both the jabs have got the right for emergency use, there has been no announcement from the government on whether it will buy the vaccines used in the immunization programme. The companies have not announced whether they will sell these vaccines in the private market. However, as the government announces boosters for front-line workers and people above 60 who are immunocompromised, these vaccines could become a potential booster shot.